Effect of Various Oxide Additives on Sintering of BaO-SiO2 System Glass-Ceramics

摘要

Glass-ceramics can be produced by sintering and crystallization of a pressedglass powder pellet. Crystallization prior to complete densification results in a porous glass-ceramic. A small quantity of various oxides was added to and melted with 35.7 BaO-64.3 SiO2(mol%) glass and the sintering characteristic of the glass powder was evaluated in terms of the density relative to the bulk glass density after heating at a constant rate. Some oxide additives, such as Al2O3 and ZrO2, increased the per cent relative density while others, such as Na2O, decreased it. The achieved per cent relative density was compared with crystallization characteristics determined by differential thermal analysis (DTA) and viscosity determined by the beam-bending method. The per cent relative density showed a good correlation with the viscosity at the crystallization temperature, the higher per cent relative density being achieved for systems with the lower viscosity at the crystallization temperature.... Glass-ceramics, Sintering.